
```
#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<math.h>
int mystrlen(const char* p)
{
    int count = 0;
    while (*p != '\0')
    {
        count++;
        p++;
    }
    return count;
}
int main()
{
    // mystrlen
    const char a[] = "abc";
    int t=0;
    t = mystrlen(a);
    printf("%d", t);

    return 0;
}
```

